A. Field of the Invention
The present invention generally relates to vacuum cleaners and, more particularly, to a new and improved vacuum cleaner with an operating condition monitoring and indicating system to provide an indication of the operating conditions of a dust collecting bag and of a wand and hose assembly.
B. Description of the Prior Art
One type of vacuum cleaner is a canister type vacuum cleaner which has a wand and hose assembly extending between a canister unit and a floor cleaning unit. One end section of the wand and hose assembly is a flexible hose which is coupled to the canister unit and the other end section is a rigid, hollow tube or wand which is coupled to the floor cleaning unit. The canister has a motor operated fan for developing suction in a dust collecting compartment. A dust bag mounted in the dust collecting compartment is adapted to be connected to a suction hose connector forming one end of the flexible hose such that when the vacuum cleaner is turned on, the suction developed in the dust collecting compartment causes air to flow into the dust bag via the floor cleaning unit, the rigid wand and the flexible hose.
The air flowing into the dust bag causes a receptacle portion of the dust bag to expand. The receptacle portion of the dust bag normally is made of porous paper. Consequently, the air flowing through the porous paper exhausts through a discharge outlet in the canister unit.
In order for the vacuum cleaner to work properly and efficiently, the dust bag must not become too clogged and the air passages within the wand and hose assembly must not become restricted. Because the dust bag is typically enclosed in the dust collecting compartment, the extent to which the dust bag has become clogged cannot be readily determined by an operator of the vacuum cleaner. Moreover, visual observation of the dust bag may not indicate whether the dust bag is clogged. In certain instances, fine dust particles or powder may coat the inner walls of the dust bag and thereby restrict the pores of the dust bag even though the quantity of debris accumulated in the dust bag does not fill the dust bag.
The volume of air flowing through the wand and hose assembly also may be lessened by a debris caused restriction in the rigid wand or in the flexible hose; however, an operator of the vacuum cleaner may have to disassemble the wand and hose assembly before determining whether such a problem has developed. Consequently, it is desirable for an operator of the vacuum cleaner to be able readily to determine whether a decrease in the cleaning performance of the vacuum cleaner is due to a restriction in the wand and hose assembly or due to a clogged dust bag.
A number of different condition monitoring and indicating systems have been disclosed in the prior art. In certain prior art patents, a sensor usually in the form of a diaphragm switch is used to monitor the differential pressure between a point at or adjacent to an intake port of the vacuum cleaner and the atmosphere to provide an indication when the dust bag is too clogged for the vacuum cleaner to operate efficiently. Examples of such patents are U.S. Pat. Nos. 4,294,595 (Bowerman); 4,481,692 (Kurz); 3,172,743 (Kowalewski); 2,320,368 (Leathers) and 2,203,171 (Martinet). In other systems, the relative pressure of the suction chamber or dust collecting compartment is monitored in order to provide a warning that the dust bag has become clogged. For instance, U.S. Pat. Nos. 4,330,900 (Dorr et al); 4,199,838 (Simonsson); 4,193,292 (Simonsson); 4,124,916 (Fromknecht); and 3,381,652 (Schaefer et al) disclose such systems. Still other patents disclose systems for indicating when the dust bag has become clogged by sensing the amount of air flowing through the vacuum cleaner. These patents include U.S. Pat. Nos. 4,342,133 (Minton) and 3,452,385 (Fleck et al). In U.S. Pat. No. 4,070,170 (Leinfelt), the differential pressure between the inside of the dust bag and the bag chamber is used to determine the extent to which the dust bag has become clogged.